Add context parameter to upsell buttons

[thijsoo]

Context

• We want to add some more parameters to our upsell buttons

Summary

This PR can be summarized in the following changelog entry:

• Adds a context parameter to upsell button links to add more context on where the button lives in the plugin.

Relevant technical choices:

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Disable premium
• Do the following in the block editor, classic and elementor.
• For the meta box, elementor and the sidebar open the following tabs and and make sure all the buttons and links that lead to a RTU page and with a context variable. and they start with the editor you are using and then location so for example elementor-sidebar
• Also make sure that when you hit a button or link it still sends you to the url attached to the button.
  SEO analysis tab
  Premium SEO analysis
  Add related keyphrase
  Readability analysis
  Facebook preview
  Twitter preview
  Insights

It could be that the links for the social previews go to the yoast.com homepage. These were changed in #19272 and can be not added to the yoa.st shortlinker yet

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Block/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change.

Quality assurance

• I have tested this code to the best of my abilities
• I have added unit tests to verify the code works as intended
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.

Innovation

• No innovation project is applicable for this PR.
• This PR falls under an innovation project. I have attached the innovation label and noted the work hours.

Fixes #

[igorschoester]

CR & ACC ✅